Sweden great Ibrahimovic, who on Tuesday confirmed he is to come out of international retirement, suffered a thigh injury in the 2-1 Serie A win at Roma on February 28 and has not featured since.
It meant Ibrahimovic missed the Rossoneri's Europa League last-16 first-leg tie against his former club at Old Trafford last week, in which Milan secured a useful away goal in a 1-1 draw.
However, Ibrahimovic has trained for an injury-hit Milan this week and is in line to play a part in a crucial second leg at San Siro.
Ismael Bennacer is also back involved but head coach Pioli still has several other issues to contend with.
"Ibra and Bennacer are recovered, they are important for us and they are among the squad," Pioli said.